jetgpio.h File Reference

#include <stddef.h>
#include <stdint.h>

Include dependency graph for jetgpio.h:

Go to the source code of this file.

Functions
int	gpioInitialise (void)
	Initialises the library. gpioInitialise must be called before using the other library functions, it stores the status of all the relevant registers before using/modifying them. More...
void	gpioTerminate (void)
	Terminates the library. This function restores the used registers to their previous state and releases memory. More...
int	gpioSetMode (unsigned gpio, unsigned mode)
	Sets the GPIO mode, typically input or output. More...
int	gpioRead (unsigned gpio)
	Reads the GPIO level, on or off, 0 or 1. Arduino style: digitalRead. Wheter a pin has been set as input or output it can be read with this function. More...
int	gpioWrite (unsigned gpio, unsigned level)
	Sets the GPIO level, on or off. Arduino style: digitalWrite. More...
int	gpioSetISRFunc (unsigned gpio, unsigned edge, unsigned debounce, unsigned long *timestamp, void(*f)())
	Registers a function to be called (a callback) whenever the specified. More...
int	gpioSetPWMfrequency (unsigned gpio, unsigned frequency)
	Sets the frequency in hertz to be used for the GPIO. More...
int	gpioPWM (unsigned gpio, unsigned dutycycle)
	Starts PWM on the GPIO, dutycycle between 0 (off) and range (fully on). Arduino style: analogWrite. More...
int	i2cOpen (unsigned i2cBus, unsigned i2cFlags)
	This returns a handle for the device at the address on the I2C bus. More...
int	i2cClose (unsigned handle)
	This closes the I2C device associated with the handle. More...
int	i2cWriteByteData (unsigned handle, unsigned i2cAddr, unsigned i2cReg, unsigned bVal)
	This writes a single byte to the specified register of the device associated with handle. More...
int	i2cReadByteData (unsigned handle, unsigned i2cAddr, unsigned i2cReg)
	This reads a single byte from the specified register of the device associated with handle. More...
int	i2cWriteWordData (unsigned handle, unsigned i2cAddr, unsigned i2cReg, unsigned wVal)
	This writes two bytes to the specified consecutive register(s) of the device associated with handle. More...
int	i2cReadWordData (unsigned handle, unsigned i2cAddr, unsigned i2cReg)
	This reads two bytes from the specified consecutive register(s) of the device associated with handle. More...
int	spiOpen (unsigned spiChan, unsigned speed, unsigned mode, unsigned cs_delay, unsigned bits_word, unsigned lsb_first, unsigned cs_change)
	This function returns a handle for the SPI device on the channel. Data will be transferred at baud bits per second. The flags may be used to modify the default behaviour of a 4-wire operation, mode 0, active low chip select. There are 2 SPI channels called SPI1 & SPI2 on Nano and SPI0 & SPI1 on Orin Nano, Orin NX and Xavier NX. For Orin AGX there is only 1 SPI channel: SPI1 (pins 21, 19...so forth). The pins used are given in the following table. More...
int	spiClose (unsigned handle)
	This functions closes the SPI device identified by the handle. More...
int	spiXfer (unsigned handle, char *txBuf, char *rxBuf, unsigned len)
	This function transfers len bytes of data from txBuf to the SPI device associated with the handle. Simultaneously len bytes of data are read from the device and placed in rxBuf. More...
int	extPeripheralRate (unsigned clk_name, unsigned rate)
	Orin family only. This functions changes the rate of one of the external peripheral clocks. There are 2 (pins 29 and 31) in Orin Nano and only one (pin 7) in Orin AGX. More...
int	extPeripheralEnable (unsigned clk_name)
	Orin family only. This functions enables one of the external peripheral clocks. There are 2 (pins 29 and 31) in Orin Nano and only one (pin 7) in Orin AGX. More...
int	extPeripheralDisable (unsigned clk_name)
	Orin family only. This functions disables one of the external peripheral clocks. There are 2 (pins 29 and 31) in Orin Nano and only one (pin 7) in Orin AGX. More...

Function Documentation

extPeripheralDisable()

int extPeripheralDisable

(

unsigned

clk_name

)

Orin family only. This functions disables one of the external peripheral clocks. There are 2 (pins 29 and 31) in Orin Nano and only one (pin 7) in Orin AGX.

Parameters

clk_name

possible values are: EXTPERIPH3 -> pin 29 Orin Nano, EXTPERIPH4 -> pin 31 Orin Nano and pin 7 in Orin AGX

Returns

Returns 0 if OK, otherwise a negative number

extPeripheralDisable(EXTPERIPH3); // disabling clock routed to pin 29 in Orin Nano 

extPeripheralEnable()

int extPeripheralEnable

(

unsigned

clk_name

)

Orin family only. This functions enables one of the external peripheral clocks. There are 2 (pins 29 and 31) in Orin Nano and only one (pin 7) in Orin AGX.

Parameters

clk_name

possible values are: EXTPERIPH3 -> pin 29 Orin Nano, EXTPERIPH4 -> pin 31 Orin Nano and pin 7 in Orin AGX

Returns

Returns 0 if OK, otherwise a negative number

extPeripheralEnable(EXTPERIPH3); // enabling clock routed to pin 29 in Orin Nano 

extPeripheralRate()

int extPeripheralRate	(	unsigned	clk_name,
		unsigned	rate
	)

Orin family only. This functions changes the rate of one of the external peripheral clocks. There are 2 (pins 29 and 31) in Orin Nano and only one (pin 7) in Orin AGX.

Parameters

clk_name	possible values are: EXTPERIPH3 -> pin 29 Orin Nano, EXTPERIPH4 -> pin 31 Orin Nano and pin 7 in Orin AGX
rate	number between 3200000 to 51000000, this is the value of the clock in Hz

Returns

Returns 0 if OK, otherwise a negative number

extPeripheralRate(EXTPERIPH3, 25000000); // setting up clock routed to pin 29 in Orin Nano to 25MHz 

gpioInitialise()

int gpioInitialise

(

void

)

Initialises the library. gpioInitialise must be called before using the other library functions, it stores the status of all the relevant registers before using/modifying them.

Returns

Returns 0 if OK, otherwise a negative number

 if (gpioInitialise() < 0)
{
  // jetgpio initialisation failed.
}
else
{
  // jetgpio initialised okay.
} 

gpioPWM()

int gpioPWM	(	unsigned	gpio,
		unsigned	dutycycle
	)

Starts PWM on the GPIO, dutycycle between 0 (off) and range (fully on). Arduino style: analogWrite.

Parameters

gpio	Nano & Xavier NX: 32, 33 Orin Nano,NX: 15, 32, 33 Orin AGX: 13, 15, 18
dutycycle	0-256 (0 to 100%)

Returns

Returns 0 if OK, a negative number otherwise

gpioPWM(32, 256); // Sets pin 32 full on.
gpioPWM(33, 128); // Sets pin 33 half on. 

gpioRead()

int gpioRead

(

unsigned

gpio

)

Reads the GPIO level, on or off, 0 or 1. Arduino style: digitalRead. Wheter a pin has been set as input or output it can be read with this function.

Parameters

gpio	3-40, 7-40 on Xavier NX dev kit

Returns

Returns the GPIO level if OK, otherwise a negative number

printf("pin 24 is level %d", gpioRead(24)); 

gpioSetISRFunc()

int gpioSetISRFunc	(	unsigned	gpio,
		unsigned	edge,
		unsigned	debounce,
		unsigned long *	timestamp,
		void(*)()	f
	)

Registers a function to be called (a callback) whenever the specified.

GPIO interrupt occurs. This function will start a thread that will monitor the status of the interrupt.One function may be registered per GPIO.

Parameters

gpio	3-40, 7-40 on Xavier NX dev kit
edge	RISING_EDGE, FALLING_EDGE, or EITHER_EDGE
debounce	0-1000 useconds, to avoid bouncing specially on mechanical inputs
timestamp	timestamp of the detected edge in nanoseconds in EPOCH format
f	the callback function, this will be execute if an edge is detected in the selected pin

Returns

Returns 0 if OK, otherwise a negative number

gpioSetISRFunc(3, RISING_EDGE, 1000, &timestamp, &callback); // Calls the 'callback' function when a rising edge is detected on pin 3, with a debouncing time of 1000 useconds
it also delivers the event timestamp on the "timestamp" variable in EPOCH format (nanoseconds) 

gpioSetMode()

int gpioSetMode	(	unsigned	gpio,
		unsigned	mode
	)

Sets the GPIO mode, typically input or output.

Parameters

gpio	3-40, 7-40 on Xavier NX dev kit
mode	JET_INPUT, JET_OUTPUT

Returns

Returns 0 if OK, -1 otherwise

gpioSetMode(17, JET_INPUT);  // Sets pin 17 as input. 

gpioSetMode(18, JET_OUTPUT); // Sets pin 18 as output. 

gpioSetPWMfrequency()

int gpioSetPWMfrequency	(	unsigned	gpio,
		unsigned	frequency
	)

Sets the frequency in hertz to be used for the GPIO.

Parameters

gpio	Nano & Xavier NX: 32, 33 Orin Nano,NX: 15, 32, 33 Orin AGX: 13, 15, 18
frequency	25Hz to 187 kHz on Nano and 50 Hz to 1593 kHz on Orin and Xavier

Returns

Returns 1 if OK, a negative number otherwise

gpioSetPWMfrequency(32, 10000); // Setting up PWM frequency=10kHz @ pin 32 

gpioTerminate()

void gpioTerminate

(

void

)

Terminates the library. This function restores the used registers to their previous state and releases memory.

Returns

Returns nothing

gpioTerminate(); 

gpioWrite()

int gpioWrite	(	unsigned	gpio,
		unsigned	level
	)

Sets the GPIO level, on or off. Arduino style: digitalWrite.

Parameters

gpio	3-40, 7-40 on Xavier NX dev kit
level	0-1

Returns

Returns 0 if OK, otherwise a negative number

gpioWrite(24, 1); // Sets pin 24 high. 

i2cClose()

int i2cClose

(

unsigned

handle

)

This closes the I2C device associated with the handle.

Parameters

handle

>=0, as returned by a call to [i2cOpen]

Returns

Returns 0 if OK, otherwise a negative number

i2cClose(MPU6050); //Closing previously opened connection 

i2cOpen()

int i2cOpen	(	unsigned	i2cBus,
		unsigned	i2cFlags
	)

This returns a handle for the device at the address on the I2C bus.

Parameters

i2cBus	0 or 1, 0 are pins 27 (SDA) & 28 (SCL), 1 are pins 3(SDA) & 5(SCL) In Orin the pins are the same but the i2c devices are: 0->i2c-1 & 1->i2c-7 In Xavier NX the pins are the same but the i2c devices are: 0->i2c-1 & 1->i2c-8 Flags allow you to change the bus speed. NOTE - FLAGS WILL NOT CAUSE ANY EFFECT FOR MACHINES WITH JETPACK >= 6:
i2cFlags	0 -> 100 kHz
i2cFlags	1 -> 400 kHz
i2cFlags	2 -> 1 MHz

Returns

Returns a handle with the I2C bus number being opened (>=0) if OK, otherwise a negative number

int MPU6050 = i2cOpen(0,0); //Opening a connection on pins 27/28 at speed 100kHz 

i2cReadByteData()

int i2cReadByteData	(	unsigned	handle,
		unsigned	i2cAddr,
		unsigned	i2cReg
	)

This reads a single byte from the specified register of the device associated with handle.

Parameters

handle	>=0, as returned by a call to [i2cOpen]
i2cAddr	0-0x7F, the I2C slave address
i2cReg	0-255, the register to read

Returns

Returns the byte read (>=0) if OK, otherwise a negative number

gyro_x_H = i2cReadByteData(MPU6050, 0x68, 0x43); // getting register 0x43 out of opened connection MPU6050 with i2C address 0x68 

i2cReadWordData()

int i2cReadWordData	(	unsigned	handle,
		unsigned	i2cAddr,
		unsigned	i2cReg
	)

This reads two bytes from the specified consecutive register(s) of the device associated with handle.

Parameters

handle	>=0, as returned by a call to [i2cOpen]
i2cAddr	0-0x7F, the I2C slave address
i2cReg	0-255, the register to read

Returns

Returns the word read (>=0) if OK, otherwise a negative number

gyro_x_H = i2cReadWordData(MPU6050, 0x68, 0x43); // getting register 0x43 and 0x44 out of opened connection MPU6050 with i2C address 0x68 

i2cWriteByteData()

int i2cWriteByteData	(	unsigned	handle,
		unsigned	i2cAddr,
		unsigned	i2cReg,
		unsigned	bVal
	)

This writes a single byte to the specified register of the device associated with handle.

Parameters

handle	>=0, as returned by a call to [i2cOpen]
i2cAddr	0-0x7F, the I2C slave address
i2cReg	0-255, the register to write
bVal	0-0xFF, the value to write

Returns

Returns 0 if OK, negative number otherwise

writestat = i2cWriteByteData(MPU6050, 0x68, 0x1B, 0x00); // writing 0x00 to register address 0x1B on opened chanel MPU6050 with i2C address 0x68 

i2cWriteWordData()

int i2cWriteWordData	(	unsigned	handle,
		unsigned	i2cAddr,
		unsigned	i2cReg,
		unsigned	wVal
	)

This writes two bytes to the specified consecutive register(s) of the device associated with handle.

Parameters

handle	>=0, as returned by a call to [i2cOpen]
i2cAddr	0-0x7F, the I2C slave address
i2cReg	0-255, the register to write
wVal	0-0xFFFF, the value to write

Returns

Returns 0 if OK, negative number otherwise

writestat = i2cWriteWordData(MPU6050, 0x68, 0x1B, 0x0000); // writing 0x0000 to register address 0x1B & 0x1C on opened chanel MPU6050 with i2C address 0x68 

spiClose()

int spiClose

(

unsigned

handle

)

This functions closes the SPI device identified by the handle.

Parameters

handle

>=0, as returned by a call to [spiOpen]

Returns

Returns 0 if OK, otherwise a negative number

spiClose(SPI_init); //closing previously opened spi port with handle SPI_init 

spiOpen()

int spiOpen	(	unsigned	spiChan,
		unsigned	speed,
		unsigned	mode,
		unsigned	cs_delay,
		unsigned	bits_word,
		unsigned	lsb_first,
		unsigned	cs_change
	)

This function returns a handle for the SPI device on the channel. Data will be transferred at baud bits per second. The flags may be used to modify the default behaviour of a 4-wire operation, mode 0, active low chip select. There are 2 SPI channels called SPI1 & SPI2 on Nano and SPI0 & SPI1 on Orin Nano, Orin NX and Xavier NX. For Orin AGX there is only 1 SPI channel: SPI1 (pins 21, 19...so forth). The pins used are given in the following table.

Port	MISO	MOSI	SCLK	CS0	CS1
SPI1/SPI0	21	19	23	24	26
SPI2/SPI1	22	37	13	18	16

Parameters

spiChan	0-1 (0 stands for SPI1 on Nano, SPI0 on Orin Nano and SPI1 on Orin AGX, 1 stands for SPI2 on Nano and SPI1 on Orin Nano)
speed	up to 50M (beyond that expect problems, actually we are not going beyond that)
mode	defines the SPI mode

Mode	POL	PHA
0	0	0
1	0	1
2	1	0
3	1	1

Parameters

cs_delay	delay if nonzero, how long to delay after the last bit transfer in us before optionally deselecting the device before the next transfer
bits_word	bits per word from 1 to 32 bits
lsb_first	is 1 if least significant bit first 0 otherwise
cs_change	is 1 to deselect device before starting the next transfer otherwise 0

Returns

Returns a handle (>=0) if OK, otherwise a negative number

SPI_init = spiOpen(1, 5000000, 0, 0, 8, 1, 1); // SPI2 (pins 22/37, 500 kHz, mode 0, cs delay 0, 8 bits/word,lsb first 1, cs change 1 

spiXfer()

int spiXfer	(	unsigned	handle,
		char *	txBuf,
		char *	rxBuf,
		unsigned	len
	)

This function transfers len bytes of data from txBuf to the SPI device associated with the handle. Simultaneously len bytes of data are read from the device and placed in rxBuf.

Parameters

handle	>=0, as returned by a call to [spiOpen]
txBuf	the data bytes to write
rxBuf	the received data bytes
len	the number of bytes to transfer

Returns

Returns the number of bytes transferred if OK, otherwise a negative number.

spiXfer(SPI_init, tx, rx, 7); // transfers tx data with a data lenght of 7 words and  receiving rx data from prevously opened connection with handle SPI_init